Manufacture of steel.



Warren Sterne PATENT Urrrcn.

WILLIAM WHITE, JR, OF PITTSBURG PENNSYLVANIA.

MANUFACTURE or STEEL;

srncrnroerrolv forming part r Letters Patent No.

695,256, dated March 11. 1902.

Application filedJuly 11. 1901. Serial No. 67,901. (No specimens.

To all whom it may concern:

' Be it known that I, WILLIAM WHITE, Jr., a citizen of the United States, residingat Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented or discovered certain new and useful Improvements in the 7 Manufacture of steeh-ofwhich improvements the following is a specification.

The invention described herein relates to .certain improvements in the manufacture of sible to make more than twelve to eighteenheats a Week, dependent upon the percentage of silicon,:carbon, 4%., contained in the metal treated and the extent of elimination required. The long time required in the treatment of the metal in the open-hearth process is due largely to the factthat the eliminations 'or reductions of the silicon, carbon, &c., are

. to'a large extent successive, being effected at bessemerized' metal in the open-hearth proc-- different temperatures-that is to say, the elimination of the silicon occurs at a lower temperature than that of the carbon and ceases almost entirely at the temperature at which the carbon is eliminated most efiic'iently by reason of the greater affinity between oxygen and carbon at such a high tern perature. Ithas been attempted to employ ess,the silicon,carbon,&c.,being eliminated as far as possible in the converter and the metal transferredto the open hearth for further treatment. This method has not been practically successful as the metal is too hot after treatment in the converter and must be allowed to cool before open-hearth treatment can begin, and, further, in the bessemerizing treatment the temperature is increased so rapidly by the oxidation of the silicon that it passesbeyond the desiliconizing temperture before all or the desired percentage of silicon is eliminated, so that the metal when transferred to the open hearth is too high in silicon, and such excess must be removed in the open hearth.

In the practice of my invention molten,

metal at a desiliconizing temperature is charged into a converter and blown to effect an elimination of the silicon. In the oxidation out of the silicon from a fifteen-ton charge containing two per cent. silicon between nine I and ten million heat units will be developed by the continuation of the blast for ten minutes. The development of this heat unless neutralized would soon raise the metal beyond the desiliconizing temperature-4. e., to

a temperature at which the oxygen has greater affinity for carbon than silicon-and that before the silicon has been sufliciently eliminated. Hence I provide for maintaining the metal at a desiliconizing temperature until the carbon lines in the spectrum show that elimination of carbon is actually progressing. A convenient means for preventing an injurious or detrimental increase of temperature by the burning of the silicon consists in forcing steam into charge of metal containing two per cent. silicon steamat or about one hundred and twenty-five pounds pressure be forced into the converter with the air. 7 5 'I have found that if in treating a fifteen-ton the converter through a pipe one and a half inches in diameter. the metal can be main-' tained 'at a desiliconizing temperature and any desired percentage of silicon removed.

.As soon as all or the desiredpercentage of silicon has been removed the'metal is transferred to an open-hearth furnace by any suitable means and there treated for the removal of carbon or phosphorus or impuritiesbyany of the usual or known methods.

It will be understood by those skilled in the 9 art that during the latter part of the treatment in the converter the steam may be partially or entirely out off, so that the temperature of the metal will be increased to or nearly to the point at which carbon is oxidized, so that when charged into the open-hearth furna'ce deca'rburization may proceed immediately, and there will not be any delay in' heating the bath to the required temperature. As

there will not be any material oxidation of 100 the iron in the'converter as long as either silicon or ca on is present, the metal will Iclaim he'reinas my invention- 1.-- 'As an'iniprovement in the art of mannfaeturing steel, the method herein described which consists in charging molten metal into ferring the desiliconized a converter, blowing air through the metal to remove the silicon, neutralizing the heat developed by the burning oi the silicon, transhearth furnace and subjecting it to the usual or any desired treatment, substantially as set forth. I l

2. As an improvement in the artof .mannmetal to an open-' facturing steel, the method herein described, which consists in subjecting molten metal to the action of a blast of air for the removal of the silicon; neutralizing the heat developed by the burningof the silicon and finally subjecting the desiliconized metal to treatment in an open-hearth furnace, substantially as set forth.

3. As an improvement in the art of manu facturing steel, the method herein described, which consists in' charging molten metal into a co'nverter,.forcing air and steam through the metal, transferring the metal when desiliconized to an open-hearth furnace, and treating it therein in the usual or any desired manner, substantially as set forth.

" In testimony whereof I have hereunto set' my hand.

' WILLIAM WHITE, JR. Witnesses:

DARWIN S. WOLCOT'J.

F. E. GAITHEB- 

